Lamella lepidocrocite particles and process for producing the same

Abstract

The disclosure describes lamella lepidocrocite particles containing 10 to 30 atm % of titanium calculated as Ti/(Ti+Fe) and having a BET specific surface area of 150 to 350 m 2 /g.

What is claimed is: 
     
       1. An oxidation catalyst for waste water treatment comprising 90 to 99.95 wt % of oxides comprising iron and titanium containing lamella lepidocrocite particles containing 10 to 30 atm % titanium, calculated as Ti/(Ti+Fe), and having a BET specific surface area of 150 to 350 m 2  /g, and 0.05 to 10 wt % of at least one element selected from the group consisting of cobalt, nickel, cerium, silver, gold, platinum, palladium, rhodium, ruthenium and iridium. 
     
     
       2. The oxidation catalyst for waste water treatment according to claim 1, wherein the lamella lepidocrocite particles have an average major axial diameter of 0.05 to 0.2 μm, a average minor axial diameter of 0.01 to 0.05 μm, and a thickness of 30 to 100 Å. 
     
     
       3. The oxidation catalyst for waste water treatment according to claim 1, wherein the lamella lepidocrocite particles have an average major axial diameter of 0.08 to 0.15 μm, an average minor axial diameter of 0.02 to 0.05 μm, and a thickness of 30 to 70 Å. 
     
     
       4. Lamella lepidocrocite particles containing titania of 10 to 30 atm %, calculated as Ti/(Ti+fe), and having a BET specific surface area of 150 to 350 m 2  /g, an average major axial diameter of 0.05 to 0.2 μm, an average minor axial diameter of 0.01 to 0.05 μm and a thickness of 30 to 100 Å. 
     
     
       5. Lamella lepidocrocite particles according to claim 4, wherein the average major axial diameter is 0.08 to 0.15 μm, the average minor axial diameter is 0.02 to 0.05 μm, and the thickness is 30 to 70 Å. 
     
     
       6. A process for producing lamella lepidocrocite particles, comprising the steps of: reacting an aqueous ferrous salt solution, an aqueous titanium solution containing 10 to 30 atm % of titanium, calculated as Ti/(Ti+Fe), based on the Fe in said aqueous ferrous salt solution, and an aqueous alkali carbonate solution, to form an iron-containing precipitate containing titanium; and   oxidizing the resultant suspension containing said precipitate in a temperature range of 5° to 40 ° C. by passing an oxygen-containing gas thereinto while maintaining the pH of said suspension at 8.0 to 10.0.   
     
     
       7. Lamella lepidocrocite particles produced by the process of claim 6.